Because research into the neurology associated with visual processing is ongoing, there is renewed debate regarding the exact timing of changes in perception that lead to chronostasis.
In studying chronostasis and its underlying causes, there is potential bias in the experimental setting.
What if the user sets back the clock, restores the harddrive image from yesterday and replicates all input/output as if it was seen the day before.
You likely are storing a license file on the system.
Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. See the How to Ask page for help clarifying this question. A user could "restore" his entire computer so that the software thinks its running at any particular date.
You could make it harder by letting the program ask some time-server for the time.
a) include the time that the software was registered in the license file, b) digitally sign the file.
This effect can extend apparent durations by up to 500 ms and is consistent with the idea that the visual system models events prior to perception.
If not, the time will tell you when the software was registered; if the "current time" is less than the registered time, your license manager knows something funny is going on and it can respond according (refuse to run, delete the license, ...
If you really want to enforce the date range, write the current time on each program execution to a separate digitially signed file, verifying that time always goes monotonically up.
Overall, chronostasis occurs as a result of a disconnection in the communication between visual sensation and perception.
Sensation, information collected from our eyes, is usually directly interpreted to create our perception.